Profession: physicist

Nollet was a serious experimenter, a scientific showman, and purveyor of scientific instruments to the wealthy, Voltaire included. He assisted du Fay and Réaumur at the Académie des Sciences. Franklin (with whom he disagreed), Spallanzani (with curiously-overlapping interests) and Volta were correspondents. In Leyden, Nollet visited Desaguiliers, s’Gravesande and Musschenbroek (who invented the Leyden jar — named by Nollet — and showed him a way of making moving images). Lavoisier, Monge and Coulomb were among his students. After visiting, he corresponded for 2 decades with Bassi, Europe’s first female professor.

Chladni lived in the same house as Weber’s family, and inspired the teenager. Weber first met the older Gauss, who was responsible for his appointment to Göttingen, at Humboldt’s; they became good friends and collaborated closely for six years, setting up the world’s first telegraph, over 3km connecting observatory and university. Friedrich Kohlrausch (later an important collaborator), Siemens, and Riemann were all students of Weber’s, and Dirichlet another close friend and colleague (he took in Dirichlet’s children after both parents died suddenly). Weber met Fechner through his brothers, during his politically-related banishment from Göttingen.

Kirchhoff made fundamental contributions to electrical-circuit theory, spectroscopy and black-body radiation, producing seminal work even while a student of the influential Neumann). He met his colleague, long-term collaborator and strong friend Bunsen when both were at Breslau, later following him to Heidelberg; Mendeleev, Meyer, Schröder, Auer von Welsbach, Kamerlingh Onnes and Roscoe were among their research students. Kirchhoff’s friend and former student Helmholtz ultimately enticed him to Berlin, where Planck (who admired him but found him dry) and Hertz also studied with him.

Kamerlingh Onnes led the world in low-temperature physics and discovered superconductivity. Bunsen and Kirchhoff taught him, while his close friend van der Waals’ theoretical work strongly supported his own practical research. Lorentz, a distant cousin, was also a close colleague at Leiden, where Ehrenfest also joined them. Dewar, Bohr and Langevin were all correspondents. The young Einstein wrote to Kamerlingh Onnes about a studentship, but got no reply; they later forged a close connection, Einstein enjoying frequent visits to Leiden, though he felt that Kamerlingh Onnes lacked skill at expressing his thoughts.